Base plate for mortars and the like



June 14, 1960 J. R. JASSE BASE PLATE FOR MORTARS AND THE LIKE 2Sheets-Sheet 1 Filed July 17, 1957 June 14, 1960 Filed July 1'7, 1957 J.R. JASSE BASE PLATE FOR MORTARS AND Tl'iE LIKE 2 Sheets-Sheet 2 BASEPLATE FOR MORTARS AND THE LIKE Joseph Raymond Jasse, Paris, France,assignor to Hotchkiss-Brandt, Paris, France, a French body corporateFiled July 17, 1957, Ser. No. 672,476

Claims priority, application France July 18, 1956 7 Claims. (Cl. 89-37)The present invention relates to base plates for mortars or like firingdevices adapted to be anchored in the ground for receiving the thrust ofthe tube of the firing device when firing.

The object of the invention is to provide a base plate which is simplein construction, particularly convenient to use and permits obtaining aremarkable stabilization of the firing device after the first shots,this plate being easy to extract from the ground after firing.

This base plate comprises in combination: a flat panel provided at itscentre with a cup or other device adapted to receive the rear end of thefiring device, and, protruding from the lower face of this panel, on onehand, fins perpendicular to the panel the lower edges of these finsforming ground-penetrating points and, on the other hand, inclinedcurved walls forming arches which are symmetrical in pairs so as toconstitute supporting wedges in the ground, said walls being upwardlydivergent and higher than said lower edges of said fins.

Owing to this construction as soon as the first shots are fired, thebase plate is driven into the ground a certain distance very rapidlyalong the parts of the fins which protrude downwardly relative to thecurved walls, the latter then progressively bear against the ground anddamp or brake from that moment on the speed at which the base plate isdriven into the ground while providing the base plate with a very largeground-contacting surface.

In this way, the surface of the base plate bearing against the groundincreases progressively and continuously with the penetration whenanchoring the base plate in the ground.

Experiments have shown that there is obtained a. first very rapidstabilization sufficient to ensure correct direction of firing for thefirst shots, and thereafter an excellent seating of the base plate evenin very soft or loose grounds.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawings towhich the invention is in no way limited.

In the drawings:

Fig. 1 is a vertical axial sectional view of a base plate embodying theinvention taken along line 11 of Fig. 2;

Fig. 2 is a plan view thereof;

Fig. 3 is a side view corresponding to Fig. 1;

Fig. 4 is a view of the underside of the base plate;

Fig. 5 is a vertical sectional view taken along line 5-5 of Fig. 1;

Fig. 6 is a perspective view from above, and

Fig. 7 is a perspective view from below.

In the illustrated embodiment of the invention, the base plate comprisesa flat panel 1 in the form of a three-branched star, for examplecomposed of weldable steel plate. Preferably this panel has at itscentre a rein-forced part 2, for example attached by welding, in whichan upper recess 3 is formed, this recess being part-spheri cal in shapethe centre 0 of which is situated in the im- 2,949,364 Patented June 14,1960 mediate vicinity and preferably slightly above the upper faceof-the panel 1.

Outside the part 2, the branches of the star-shaped panel 1 could have aconstant thickness or, as is shown in Fig. l, a thickness tapering fromthe part 2 toward the ends 4 of the branches (Figs. 1 and 6). Thesebranches have lateral parallel edges interconnected by large-radiusarcuate edges 5 (Figs. 2 and 6).

Fixed under the panel 1 are three fins 6 composed of thin plates. Eachfin is disposed in a radial plane which is the median plane of one ofthe branches of the panel 1. The fins 6, which meet at the vertical axisXX intersecting the centre 0 of the recess 3, are interconnected bywelding at 7 on this axis.

On the centre of the base plate, under the reinforced part 2 of thepanel, the fins 6 are furthermore interconnected by a conical wall 8which terminates at its base in a conical end member 9 the point ofwhich is directed downwardly.

The lower edges 11 of the fins are parallel with the panel 1 in theirportion in the vicinity of the centre of the; base plate but these edgesprogressively curve downwardly at 12 and terminate in a peripheral point13 which: constitutes one of the three bearing points of the base: platethe most distant from the panel 1 in the down-- ward direction. Thecentral point 9 is distinctly nearer:

the panel 1 than the peripheral point 13.

Each point 13 pertaining to one of the fins is reinforced by aperipheral spade 14 and by two gusset plates.-

15 which connect this spade to the fins 6. Each spade:

14 consists of a triangular plate which extends a certaim distancebeyond the panel 1 and terminates in an upper large base 14* which isrectilinear in the presently-described embodimentr Preferably, thesespades 14 are slightly oblique and downwardly diverge relative to theaxis XX.

The fins 6 are each combined with a pair of inclined curved walls in theform of arch portions 16-17, Ili -17 and 16 17 The two walls of eachpair are connected at their lower edges to the corresponding fin alongtwo lines 18 on opposite sides of this fin. These lines 18 are parallelwith the panel 1 and are closer to the latter than the lower edges 11 ofthe fins.

The two walls of each pair upwardly diverge symmetrically relative tothe corresponding fin 6, that is relative to an axial radial planecontaining the axis XX, and extend beyond the panel 1 and terminate in acurved upper edge 19which is preferably reinforced. These walls arepart-conical and do not require to be pressed out when being put intoshape, this shaping being obtained by a simple rolling operation. Theangle of inclination of each of these wallsrelative to a plane parallelwith the panel 1 progressively decreases from a value a at the level ofthe line 18, to a value b at the level of the panel, to a value c at theupper end 19 of the wall. These angles could advantageously have valuesbetween the following limits:

It will be observed that at the level of the panel 1 the curved wallsare connected to the edges of this panel, these edges being chamfered atthe angle b.

As can be easily seen from the figures, the curved walls forming archespertaining to the various fins 6, are interconnected in pairs alonglines 211 situated in axial radial plans and these lines, owing to asuitable shape of said walls, could be rectilinear as seen on the rightside of Fig. l, and in Figs. 4, 6 and 7.

Adjacent the periphery of the base plate, the curved.

walls, pairs of which form a wedge-like structure as 7 shown in Fig. 5,are connected to gusset plates and spades 14 whereas at their innerparts these walls are connected to the conical wall 8 along lines 21.which are elliptical or the like and can be seen in Figs. 4, 6 and 7.

Preferably, the total area of the anchoring surfaces normal orsubstantially normal to the panel 1 (the parts of the fins 6 situatedbelow the lines 18 and the spades 14) only represent a relatively smallfraction (20 to of the total anchoring surface.

The plate is completed by arcuate handles 22, for example one handle foreach spaced 14, these handles being fixed to the latter at their ends.

The base plate of the invention is used in the following manner:

When the firing position has been selected, the base plate is placeddirectly on the ground on its three points 13 and the breach of thefiring device is engaged by its rear swivel bearing in thepart-spherical recess 3 on which the firing device is pivotable foradjusting the firing direction and elevation. As soon as the first shothas been fired, the reaction of the firing device exerts on the baseplate a downward thrust through the centre of the recess 3 and, as aresult of this thrust, the base plate is driven into the ground firstlyat its points 13 and thereafter along the lower portions of the fins 6and the spades 14.

The rapid penetration of these anchoring surfaces, which are normal orsubstantially normal to the panel, is followed in the course ofsubsequent firing by much more progressive penetration of the portionsof the curved inclined anchoring walls 1617 16 17 Owing to theWedge-like arrangement of the walls in symmetrical relation about theaxial radial planes of the base plate, the penetration of the latter inthe ground causes the ground to be pushed back in a symmetrical mannerby the lower surfaces of these walls thereby creating a tamping effectso that the reactions of the ground. have in the horizontal directionsubstantially zerocomponents. Thus the ground, as it offers a resistancewhich is the greater as the angles a, b, c are smaller, does not causethe base plate to be displaced laterally, and the stability of'this baseplate as concerns its positionat a given point in the ground ispractically perfect.

The penetration or bedding-down of the base plate in the course offiring proceeds, but with an increasing damping or braking effect, sincethe angles of the portions of the inclined and curved walls which comeinto contact with the ground decrease from a to c-as the base platepenetrates the ground and soon after a relatively small number of shots,and in any case less than ten shots, the base plate is practicallysecured in position. It is well seated on the ground and provides asubstantially immovable support for the firing device for subsequentfiring.

Tests have shown that with the variation in the angles from a to c, inground with average resistance, irrespective of the position ofpenetration of the base plate, the friction of the surfaces embedded inthe ground is suflicient to oppose any rebound due to new portions ofsurfaces entering into contact with the ground as penetra tion proceedsat the start of successive shots. 1

The base plate of the invention has other important shots.

walls 16''17 16 17 form with the fiat panel a strong box-like structurein the form of a starwhich transmits to said walls, which form archesand bear against the ground, the initial percussion of the successive Itis very easy to extract from the ground compared with most of known baseplates. The slopes due to the anglesa' to c are such that the grounddoes not adhere to the. base plate and the. latter never needs cleaning.7

Although a specific embodiment of the invention has been described,manyjmodifications and changes may be made therein without departingfrom the scope of the invention as defined in the appended claims.

Having now described my invention what I claim as new and desire tosecure by Letters Patent is:

l. A base plate for a mortar or like firing device, said base platecomprising: a flat panel including a substantially central'portion,vertical fins depending from said panel and extending radially fro-msaid central portion, said fins including pointed portions extendingdownwardly and spaced from said central portion, and a pair ofcurvedwalls operatively engaged with said panel and extending along andconverging towards a respective one of saidfins to engage therewith at aposition spaced from the bottom of said one fin, said walls being curvedin a cross-section normal to the radial extent of said one fin, saidwalls diverging upwardly for braking the displacement of the plate intothe ground after the fins have entered the ground by engaging the groundwith increasing amounts of surface area. 7

1 2. A base plate as claimed in claim 1 wherein the walls extend aboveand below the panel and define angles with the horizontal which varyfrom between 55-65 at their lowermost extremes to 45-55 at the panel and30-45 at their uppermost extremes.

3. A base plate as claimed in claim 1 wherein said walls are connectedto the respective fins along substan tially horizontal lines.

4. A base plate as claimed in claim 1 comprising spades at theperipheral ends of the fins, said spades being interconnected by theperipheral ends of adjacent pairs of said walls.

5. A, base plate as claimed in claim 4 comprising peripheral gussetplates providing a reinforced connection between said spades, fins andwalls. I

6. A base plate as claimed in claim 1 comprising a pointed memberdepending downwardly from the center of said panel and interconnectingthe fins.

7. A base plate as claimed in claim 6 wherein said member includes twoconnected sections in vertical alignment,.the upper section being ofinverted truncated cone shape,.the lower section being of invertedconical shape;

References Cited in the file of this patent UNITED STATES PATENTS2,557,960 Gerhardt June 26, 1951 2,694,342 Canonne Nov. 16, 1954 FOREIGNPATENTS 7 816,093 France Apr. 26, 1937

